金絲小棗蛋白聚糖的分離及其結構分析   全文下載

Isolation and Analysis of a Novel Proteoglycan from Zizyphus jujuba cv. Jinsixiaozao

紅棗作為藥食同源植物，具有許多生理活性。本文對金絲小棗蛋白聚糖的提取純化方法、結構以及它對補體系統的影響進行了研究。以棗果為材料，經熱水抽提、乙醇沉澱、陰離子交換管柱層析和凝膠管柱層析，分離純化得白色粉末狀棗蛋白聚糖（ZSG4b）。ZSG4b經高效凝膠滲透層析和凝膠管柱層析鑑定為均一組分，測得其分子量為1.4 × 105 Da。化學組成分析顯示ZSG4b含83.5%多糖，9.7%蛋白質。氣相層析顯示ZSG4b含鼠李糖、阿拉伯糖、甘露糖、半乳糖，其莫耳比為13.8:4:3:8；胺基酸組成分析顯示ZSG4b富含天冬胺酸、麩胺酸、絲胺酸、蘇胺酸和白胺酸，這五種胺基酸占總胺基酸莫耳百分比的62.8%。β-消去反應顯示ZSG4b中的多糖與蛋白質系由O-型糖?鍵結合。ZSG4b在體外有明顯的抗補體活性，活性隨其濃度的增大而增加。

Chinese jujube (Zizyphus jujuba Miller) is a well-known oriental medicinal plant that has various biological activities. In this study, a novel water-soluble proteoglycan (ZSG4b) was isolated from Zizyphus jujuba cv. Jinsixiaozao and its effect on the complement system was investigated. ZSG4b was extracted with hot water and purified by DEAE-Sepharose CL-6B and Sepharose CL-6B column chromatography. It was eluted as a single symmetrical narrow peak on high-performance gel-permeation chromatography (HPGPC) and the average molecular weight was estimated to be 1.4 × 105 Da. ZSG4b contained 83.5% glycan and 9.7% protein. Gas chromatography analysis result indicated that the glycan portion of ZSG4b was composed mainly of rhamnose, arabinose, mannose and galactose in a molar ratio of 13.8:4:3:8. It also contains 29% uronic acid as determined by m-hydroxybiphenyl method. The presence of galacturonic acid was estimated by the increase of galactose content in the carboxyl-reduced ZSG4b. The amino acid composition showed that it was rich in aspartic acid, glutamic acid, serine, threonine and leucine; the molar content of these five amino acids constituted 62.8% of the total amino acids. The β-elimination reaction demonstrated that the protein and glycan were linked by O-linkage. ZSG4b exhibited high anti-complement activity which was increased in accordance with the concentration below 120 μg/mL in vitro.